Two-loop virtual QCD correction to the B -> X_s l+l- decay

I discuss an application of numerical techniques for massive two-loop Feynman diagram evaluation to a phenomenologically very important rare decay process, B -> X_s l+l-. This process, currently being measured at B factories, has been calculated at two-loop level in the lower dilepton invariant mass perturbative window by a previous collaboration. We extended this result, by using numerical integration methods, to the whole observable spectrum of the dilepton invariant mass consistent with the perturbative QCD regime.